Genes/Quantitative Trait Loci and Associated Molecular Mechanisms Identified in Capsicum Genome for Tolerance to Abiotic and Biotic Stresses

Abstract

Capsicum is one of the most important vegetable crops of the family Solanaceae and is widely used as spice due to its pungent nature. Besides, Capsicum fruit rich in metabolites and vitamins; and also has anti-cancerous property, which further increases the importance of this crop. However, Cap-sicum crop is highly affected by abiotic/biotic stresses such as drought, heat, cold, salinity, and pathogens. To overcome these stresses, plants adapted several mechanisms such as the production of osmoprotectant, proline, galacti-nol and raffinose, and the reduction of reactive oxygen species. Autophagy also plays an important role to provide tolerance against stresses through degradation of toxins. Among the others, transcription factors and plasma membrane intrinsic proteins, and plant endo-phytes are found to be involved in regulating stress tolerance mechanism. Furthermore, in Capsicum genome, a number of genes and quantitative trait loci (QTLs) involved in stress tolerance mechanism have been identified. In this chapter, a detail compilation of important molecular mechanisms and associated genes/QTLs involved toward imparting abiotic and biotic stress tolerance in Capsicum genome is made. 7.1 Introduction Environmental stresses including both abiotic and biotic stresses have major effects on different developmental processes in plants. To overcome these stresses, plants adopted different mechanisms including production/accumulation of osmoprotectants, chaperones, and increasing superoxide radical scavengers. Among the major abiotic stresses, drought, cold, heat, salinity, and cold stresses are the most common in Capsicum crop. Beside abiotic stresses, several pathogens also damage Capsicum crop by causing several diseases. For example, Phytophthora capsici causes rot disease on various plant parts such as root, shoot, leaf, and fruits. Several other diseases including leaf spot (caused by Xanthomonas campestris), viral disease (caused by tobacco mosaic virus TMV, cucumber mosaic virus CMV, tomato spotted wilt virus TSWV, and potyvirus) also damage Capsicum plants severely. These diseases cause retorted growth and development and ultimately reduced yield and quality of fruits.